Walk Off 350 Calories in 45 Minutes

Talk about an efficient lunch break— The Biggest Loser trainer, Bob Harper, designed a walk-it-off routine, blasting 350 calories in 45 minutes.

Do a warm-up walk for a couple of minutes; strike with your heel first, then roll into the forefoot, keeping shoulders relaxed and letting arms swing naturally.

Then up the pace—you should feel winded but still be able to speak in short bursts—and begin your first four-minute walking segment. The quicker (not longer) your steps, the better the burn.

After each walking segment, complete a power minute. You have three options: jumping jacks, sprinting, and walking lunges. You can pick just one to repeat—but for the best results, do all three.

"When you vary your moves, you avoid that dreaded shape-up plateau," explains Harper.

Pounding the pavement can help lower your level of cortisol, the body’s stress hormone that’s linked with weight gain. While running, you really want to get your heart rate up there—you should be breathless when you ease back into your walk.

Remember to keep your chin up, allowing your gaze to fall naturally a few feet in front of you. Relax your shoulders, and keep your head in line with them so your center of gravity stays at your core.

Continue sprinting for 1 minute.

Crank up your cardio with this school-yard staple. Stand with feet together and arms down by your sides. Quickly bring arms out to sides and up overhead, while jumping your feet wide apart.

Return to starting position and repeat for 1 minute.

This move targets your entire leg, from the butt to the calf.

Step your right leg forward two feet and lower until both knees are at 90 degrees; don’t let the front knee go past your toes. Push into your right heel, lifting your left leg up while stepping it forward; repeat the lunge.

Continue to alternate legs for 1 minute.

Power through at least five workouts a week: Walk briskly for four minutes, do a power minute, and repeat nine times.

Make sure to keep your core engaged to limit stress on your knees and joints, says Harper.